Heparin-Induced Thrombocytopenia (HIT) | A Comprehensive Explanation... Heparin is an anticoagulant that stimulates antithrombin III (ATIII) which then inhibits coagulation factors VII, IX, X, XI, XII, as well as thrombin. This leads to prevention of thrombus formation (anticoagulation)...Heparin is used for ICU anticoagulation...Adverse effects of heparin includes bleeding, Heparin-induced thrombocytopenia (HIT), and osteoporosis. Heparin | The blood 🩸 thinner | The Anticoagulant | Pharmacology | Hematology.